Railway-traffic-controlling apparatus



May 18 1926. 1,585,286

R. M. GILSON RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 15, 1924 if Fig.1. -*i 9 5 %:0 a Lil/E r? 4 I) C 2: 4 75 :2 1 2 g' F [m g I INVENTORI 771,, 6%, BY Z V- I:

, J-C ATTORNEY Patented May 18, 192$.

NET STATES PATENT OFFECE.

ROBERT M. GILSON, OF PITTSBURGH, PENNSYLVANIA, ASSTGNOE TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY-TRAFFIC-CONTROLLING APPARATUS.

Application filed September 15, 1924. Serial No. 737,701.

My invention relates to railway trafiic controlling apparatus, and particularly to apparatus of the type wherein train-carried governing mechanism is controlled by energy received from the trackway. More specifically my present invention relates to the trackway portion of such apparatus.

I will describe one form of apparatus embodying my invention and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view showing one form of apparatus embodying my invention. Fig. 2 is a diagrammatic view showing a modification of a portion of Fig. 1 and also embodying my invention.

Referring first to Fig. 1, the reference characters 1 and 1 designate the track rails of a railway along which traffic normally moves in the direction indicated by the arrow. These rails are divided by insulated joints 2 to form a track section A-B, and the rails of section AB are further divided by insulated joints 2 to form a forward sub-section A0 and a rear sub-sec tion CB.

The track section AB is supplied with track circuit current by a transformer D, the secondary of which is connected across the rails adjacent the point A. The primary of transformer D is connected with a transmission line G, which is constantly supplied with alternating current by a generator H. This track circuit current is conducted around the insulated joints 2 by a transformer F, the primary of which is connected across the rails of the forward subsection A-C, and the secondary of which is connected across the rails of the rear subsection CB. The connections of the transformer F, are such that the relative instantaneous polarities of the track circuit current in the two sub-sections are opposite. That is, when rail 1 of sub-section AC is positive with respect to rail 1 of this subsection, rail 1 of sub-section CB is positive with respect to rail 1 of this sub-section, and vice versa'.

Loop current is supplied to the rails of section A-B by a transformer E. One terminal of the secondary 8 of this transformer is connected with a resistence 4 which is bridged across the rails of the section adjacent the point A, and the same terminal of the secondary 8 of transformer E is also connected with a resistence 7 which is bridged across the rails adjacent the point B. The other terminal of the secondary 8 of transformer E is connected with two resistances '5 and 6 which are bridged across the rails on the opposite sides respectively of the insulated joints 2. It will be seen, therefore, that loop current flows in the two rails of each sub-section in multiple, and that at any given instant the directions in which this loop current are flowing in the two sub-sections will be opposite. That is to say, when resistance a is positive'with respect to resistance 5, resistance 7 will be positive with respect to resistance 6, and vice versa. Loop current is supplied to the primary 9 of transformer E by the secondary of a transformer J through a contact 3 of a relay K, which relay is controlled by traffic conditions in advance of the section A-B in any desired manner. The primary of transformer J is connected with the transmission line G.

Referring now to Fig. 2, the apparatus here shown is the same as that shown in Fig. 1, except that the loop transformer, which is here designated E, is provided with two secondaries 8 and 8 which secondaries supply loop current to the forward sub-section AG and the rear sub-section CB respectively. That is, the two terminals of secondary 8 are connected with resistances 4: and 5 respectively, whereas the two terminals of secondary 8 are connected with resistances 6 and 7 respectively. It follows that, as in Fig. 1, the loop current flows in the two rails of each sub-section in multiple, and at any given instant the directions in which this loop current are flowing in the two sub-sections will be opposite.

The apparatus shown in each view of accompanying drawing is intended for use in co-operation with train-carried governing mechanism which is controlled jointly by the track circuit current and the loop current in the track rails. Such train-carried mechanism is usually so constructed that a proceed indication is given when the track circuit current and the loop current have one relative polarity, and a different indication when the track circuit current and the loop current have the opposite relative polarity. When a train moving in thedirection indicated by the arrow enters the subsection C-B, it will be observed that so far as track circuit current is concerned, the right-hand rail 1 is negative with respect to the left-hand rail 1, and that far as loop current is concerned, resistance 6 ahead of the train is negative with respect to resistance 7 behind the train. This relation may be stated more briefly by saying that in sub-section 0-13 the train has n ative track circuit current on the right and negative loop current ahead. When the train occupies the forward sub-section A-U, it will have positive track circuit current on the right and positive loop current ah ad. It follows that the instantaneous relative polarities of the two currents are the same in so far as the train carried mechanism is concerned, whether the train is in the rear sub-section Cl3 or in the forward sub-section AC.

In systems of this general character, it has heretofore been proposed to connect one terminal of the loop current source with both rails at the forward end of the section and the other terminal of the loop current source with both rails at the rear end the section, the rails of the section being electrically continuous throughout. lVhen this is done it has been found that there is considerable leakage of loop current. In some instances a considerable portion of the loop current leaves the rails near one end of the section and returns to the rails near the other end of the section. By dividing the section at the point C, I have reduced the length of the loop circuit by one-half without affecting the length of the track circuit, with the result that the amount of leakage of loop current is reduced to about one fourth of the amount of leakage which would occur if a single loop circuit were carrggd throughout the length of the section A Another important feature of my invention is the reduction in the amount of leakage of loop current from the rails of section A-B through the traclr section in the rear when a train bridges the insulated joints 2 at point 13.

Still another important advantage of my invention is the opportunity of introducing a reactor in the portion of the loop circuit which feeds sub-section C-l?-, but not in the portion of the loop circuit which feeds subsection A-C. Such a reactor is shown at 10 in Fig. 52. This reactor will shift the phase of the loopcurrent for the rear portion of the section and thereby produce a better phase angle between the loop current and the track circuit current in the rear portion of the section under poor ballast conditions.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that esaeee various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what 1 claim is:

1. in combination, a section of railway track divided to form a forward and a rear sub-section, means for causing alternating track circuit current to flow in two rails of each sub-section in series, the instantaneous relative polarities of the track circuit current in the forward and the rear subsections being opposite, means for causing alternating loop current to flow in the two rails of each section in multiple in such manner that at any given instant the directions of flow in the two sub-sections are opposite, and means for shifting the phase of the loop current in the rear sub-section with respect to the phase of the loop current in the forward sub-section.

2. in combination, a section of railway track divided to form a forward and a rear sub-section, means for causing alternating track circuit current to flow in the two rails of each subsection in series, the instantaneous relative polarities of the track circuit current in the forward and rear sub-sections being opposite, and means for causing alternating ioop current to flow in the two rails of each section in multiple in such manner that at any given instant the directions of flow in the two sub-sections are opposite.

In combination, a section of railway track divided to form a forward and a rear sub-section, means for causing alternating track circuit current to flow in the two rails of each sub-section in series, the instantaneous relative polarities of the track circuit current in the forward and rear sub-sections being opposite, means for causing alternating loop current to flow in the two rails of each section in multiple in such manner that at any given instant the directions of flow in the two sub-sections are opposite, and a reactor included in the path of the loop current for the rear sub-section.

4:. In combination, a section of railway track divided at an intermediate point to form forward and rear sub-sections, a source of alternating track circuit current connected across the rails of said forward subsection, a transformer the primary of which is connected across the rails of the forward sub-section and the secondary of which is connected across the rails of the rear subsection, said transformer connections being such that the instantaneous relative polarities of the track circuit current in the forward and rear sub-sections are opposite, a source of alternating loop current having its terminals connected with both track rails adjacent the forward and rear ends respectively of said forward sub-section, and a Hit) source of alternating loop current having its terminals connected with both track rails adjacent the forward and rear ends respectively of said rear sub-section, the connections of said loop current sources being such that at any given instant the loop current flows in opposite directions in the two subsections.

5. In combination, a section of railway track divided at an intermediate point to form forward and rear sub-sections, a source of alternating track circuit current connected across the rails of said forward subsection, a transformer the primary of which is connected across the rails of the forward sub-section and the secondary of which is connected across the rails of the rear subsection, said transformer connections being such that the instantaneous relative polarities of the track circuit current in the forward and rear sub-sections are opposite, a source of alternating loop current having its terminals connected with both track rails adjacent the forward and rear ends respectively of said forward subsection, and a source of alternating loop current having its terminals connected with both track rails adjacent the forward and rear ends respectively of said rear subsection, the connections of said loop current sources being such that at any given instant the loop current flows in opposite directions in the two subsections, and a reactor included in circuit with said second source of loop current.

6. In combination, a section of railway track divided to form a forward and a rear sub-section, means for causing alternating loop current to flow in the two rails of each section in multiple in such manner that at any given instant the directions of flow in i said forward sub-section, and a transformer the primary of which is connected across the rails of the forward sub-section and the secondary of which is connected across the rails of the rear sub-section, said transformer connections being such that the instantaneous relative polarities of the track circuit current in the forward and the rear sub-sections are opposite.

8. In combination, a section of railway track divided to form a forward and a rear sub-section, and means for causing alternating track circuit current to flow in the two rails of each sub-section, in series and the instantaneous relative polarities of the track circuit current in the forward and the rear sub-sections being opposite.

In testimony whereof I affix my signature.

ROBERT M. GILSON. 

